NIR-II photothermal therapy for effective tumor eradication enhanced by heterogeneous nanorods with dual catalytic activities

Rational design and exploitation of nanomaterials with superior treatment properties for suitable indications is a way out to relieve cost constraint of therapy and solve the unsatisfactory efficacy for cancer patients. In this work, we propose a greatly facile approach to produce heterogeneous Pd-Au nanorods (Pd-Au NRs) that solve the current bottleneck problems of photothermal thermal therapy (PTT) as well as completely eliminate tumors in animal models without toxic side effects. Depositing Pd clusters on both tips of Au NRs offers Pd-Au NRs three novel functions, i.e., the extension of the absorption into NIR-II region, the activation of prodrug of 5-fluorouracil (5-Fu) via the bioorthogonal reaction, and the peroxidase-mimic activity to produce ·OH. The heterogeneous nanorods showed a high and stable photothermal conversion efficiency (52.07%) in a safer NIR-II irradiation region (1,064 nm), which not only eliminate most of tumor cells at only one dose of the irradiation for 5 min but also improve the in situ conversion of 5-fluoro-1-propargyluracil and H2O2 into active 5-Fu and ·OH to eradicate residual tumors for inhibiting tumor metastasis. This dual catalytic activity-synergistic mechanism of PTT demonstrates the importance of material design in solving current bottleneck problem of tumor therapy.